Implemented SheerkaOntology

src/core/global_symbols.py

@@ -8,3 +8,35 @@ EVENT_CONCEPT_CREATED = "evt_cc"
 # comparison context
 RULE_COMPARISON_CONTEXT = "Rule"
 CONCEPT_COMPARISON_CONTEXT = "Sya"
+
+
+class CustomType:
+
+    def __init__(self, value):
+        self.value = value
+
+    def __repr__(self):
+        return self.value
+
+    def __eq__(self, other):
+        return isinstance(other, CustomType) and self.value == other.value
+
+
+class NotInitType(CustomType):
+    def __init__(self):
+        super(NotInitType, self).__init__("**NotInit**")
+
+
+class NotFoundType(CustomType):
+    def __init__(self):
+        super(NotFoundType, self).__init__("**NotFound**")
+
+
+class RemovedType(CustomType):
+    def __init__(self):
+        super(RemovedType, self).__init__("**Removed**")
+
+
+NotInit = NotInitType()
+NotFound = NotFoundType()
+Removed = RemovedType()